This application claims the benefit of Korean Application No. 2002-67517, filed Nov. 1, 2002, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates generally to a heat sink for electronic devices, and circuit board and plasma display panel assembly, each equipped with the heat sink, and more particularly to a heat sink for electronic devices, and circuit board and plasma display panel assembly each equipped with the heat sink that is capable of reducing noise.
2. Description of the Related Art
In general, a circuit board, which is installed in various electronic apparatuses, is equipped with a plurality of electronic devices and performs programmed operations through the interaction with these electronic devices.
These electronic devices are supplied with electric power and perform predetermined operations. Some of these electronic devices generate heat and vibration according to their operational characteristics during operation.
The electronic devices that generate heat and vibration are exemplified by a Metal-Oxide Semiconductor Field Effect Transistor (MOSFET).
The MOSFET is applied to a Plasma Display Panel (PDP) to discharge electricity in each of the cells of the PDP. The MOSFET generates heat while switching on/off voltage supplied to each of the cells of the PDP.
FIG. 1 is a view showing a MOSFET 2 and a conventional heat sink 3 for electronic devices that are fixedly attached to a circuit board 1.
As illustrated in FIG. 1, the conventional heat sink 3 for electronic devices includes a base portion 3a fastened to the circuit board 1, a contact portion 3b extended from the base portion 3a and brought into contact at one side thereof with the MOSFET 2, and a plurality of heat radiation fins 3c that are extended from the contact portion 3b to be regularly spaced apart from each other.
Accordingly, heat is transmitted to the heat radiation fins 3c through the contact portion 3b of the heat sink 3, and radiated to the air through the heat radiation fins 3c.
Electromagnetic force is generated in the MOSFET 2 when the MOSFET 2 switches on the voltage, while electromagnetic force is eliminated when the MOSFET 2 switches off the voltage. Accordingly, when the MOSFET 2 is turned on/off to perform this switching operation, electromagnetic force is repeatedly generated and extinguished, thereby vibrating the MOSFET 2.
When the MOSFET 2 vibrates, a vibration is transmitted to the heat sink 3 that is used to cool the MOSFET 2. The transmitted vibration vibrates the plurality of heat radiation fins 3c of the heat sink 3, and consequently generates noise. Since the heat radiation fins 3c vibrate in proportion to the distance from the base portion 3a fastened to the circuit board 1, the heat radiation fins 3c generate noise in proportion to their distance from the base portion 3a. 
In particular, where the conventional heat sink for electronic devices is applied to a television set of a home theater system and generates excessive noise, users may complain about the excessive noise of products.
Accordingly, it is an aspect of the present invention to provide a heat sink for electronic devices, and circuit board and plasma display panel assembly, each equipped with the heat sink, which is capable of reducing noise.
Additional aspects and advantages of the invention will be set forth in part in the description that follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other aspects of the present invention are achieved by providing a heat sink for electronic devices, and circuit board and PDP assembly, each equipped with the heat sink, including a base portion fixedly attached to a circuit board, a contact portion fixedly and tightly brought into contact with one or more electronic devices, and a plurality of heat radiation fins each extended from the contact portion to a certain distance; and wherein a heat radiation fin distant from the base portion has a width shorter than that of a heat radiation fin nearer to the base portion.
A second aspect of the present invention is that one of the plurality of heat radiation fins may be fixedly attached to the circuit board and constitute the base portion.
A third aspect of the present invention is that the contact portion may be extended from the base portion to form a certain angle with the base portion, and the plurality of heat radiation fins may be extended from the contact portion parallel to the base portion.
A fourth aspect of the present invention is that a heat radiation fin spaced from the base portion by more than a predetermined distance may have a width shorter than that of a heat radiation fin situated within the predetermined distance.
A fifth aspect of the present invention is that the plurality of heat radiation fins each may have a width inversely proportional to a distance thereof from the base portion.
A sixth aspect of the present invention is that the electronic devices may be MOSFETs.